Lattice computation of the Kugo-Ojima correlation function

As of today, color confinement in Quantum Chromodynamics remains a mystery from the theoretical point of view. So far, no analytical proof of color confinement has been found and the mechanism that confines colored states from the space of physical states is still unknown. Taichiro Kugo and Izumi Ojima proposed such confinement mechanism, using as basis the BRST-symmetry and derived the requirements for the realization of this mechanism. One such requirement, which happens to be the non-trivial one, is that a special correlation function, the Kugo-Ojima correlation function $u(p^2)$, approaches $-1$ at the origin ($p^2=0)$. This correlation function can be obtained on the lattice within the lattice formulation of gauge theories. The present work consists on lattice results for this correlation function on the Landau gauge. We present results obtained from 4 symmetric large volume lattices $(32^{4}, 48^{4}, 64^{4}, 80^{4})$ with $\beta = 6.0$ on the Landau gauge. A test on the transversality of the Kugo-Ojima correlation function is also performed, along with some statistical considerations of the results. The results present further evidence that the Kugo-Ojima confinement scenario is not realized on the lattice and that the Kugo-Ojima correlation function, in the Landau gauge, is transverse. Our findings align qualitatively with existing literature.Comment: Master's Degree Dissertation, 72 Pages, 10 Figure

Diferenciação automática adjunta para o erro quadrático médio envolvendo expetações

This dissertation will have as an objective, explain how to calculate gradients of Mean Squared Error, (...), since it's applied in calibration methods of stochastic models, using the Automatic Adjoint Differentation and parallelization. With the involviment of mean values, the application of the Monte-Carlo Simulation will be needed to approximate possible expected values as well as, distinct and appropriate estimation methods for the computation of its correspondents partial derivaties. Therefore, in this document, will be initialized with the introduction of certain concepts needed, like the Automatic Adjoint Differentiation, the Monte-Carlo Simulation, as well as, Call Options of European Options since, will be used, for a pratical case, a simple stochastic model of European Call Options applying the differentiation for a certain group of parameters. Finally, such concepts introduzed previously, will be applied for the primary objective, analizing the theoretical and pratical results from which you can withdraw with the different estimation methods applied.Esta dissertação terá como objetivo, explicar como calcular gradientes do Erro Quadrático Médio, (...), uma vez que é aplicado em métodos de calibração de modelos estocásticos, utilizando a Diferenciação Automática Adjunta e computação em paralelo. Com o envolvimento de valores médios, a aplicação da Simulação de Monte- Carlo será necessária para aproximação de possíveis valores esperados tal como, métodos de estimação distintos e apropriados para a computação das suas derivadas parciais correspondentes. Por conseguinte, neste documento, será inicializado com a introdução de certos conceitos necessários, como a Diferenciação Automática Adjunta, Simulação de Monte-Carlo, assim como, Call Options de Opções Europeias uma vez que, será utilizado, para um caso prático, um modelo estocástico simples de Call Options europeias aplicando a diferenciação para um certo conjunto de parâmetros. Por fim, tais conceitos introduzidos previamente, serão aplicados para o objetivo principal, analisando os resultados teóricos e práticos de que se pode retirar com os diferentes métodos de estimação aplicados.Mestrado em Matemática e Aplicaçõe

A system’s approach to cache hierarchy-aware decomposition of data-parallel computations

Dissertação para obtenção do Grau de Mestre em Engenharia InformáticaThe architecture of nowadays’ processors is very complex, comprising several computational cores and an intricate hierarchy of cache memories. The latter, in particular, differ considerably between the many processors currently available in the market, resulting in a wide variety of configurations. Application development is typically oblivious of this complexity and diversity, taking only into consideration the number of available execution cores. This oblivion prevents such applications from fully harnessing the computing power available in these architectures. This problem has been recognized by the community, which has proposed languages and models to express and tune applications according to the underlying machine’s hierarchy. These, however, lack the desired abstraction level, forcing the programmer to have deep knowledge of computer architecture and parallel programming, in order to ensure performance portability across a wide range of architectures. Realizing these limitations, the goal of this thesis is to delegate these hierarchy-aware optimizations to the runtime system. Accordingly, the programmer’s responsibilities are confined to the definition of procedures for decomposing an application’s domain, into an arbitrary number of partitions. With this, the programmer has only to reason about the application’s data representation and manipulation. We prototyped our proposal on top of a Java parallel programming framework, and evaluated it from a performance perspective, against cache neglectful domain decompositions. The results demonstrate that our optimizations deliver significant speedups against decomposition strategies based solely on the number of execution cores, without requiring the programmer to reason about the machine’s hardware. These facts allow us to conclude that it is possible to obtain performance gains by transferring hierarchyaware optimizations concerns to the runtime system

The Effects of a Technology Shock in the Euro Area

The aim of this paper is to estimate the effects of a technology shock in the euro area within a structural VAR framework. Since the impact of these shocks on labor use is a controversial issue in the related literature, we give particular attention to it. Given that the estimated effects of a technology shock are quite sensible to the low-frequency properties of the labor input measure, we resort to an extensive statistical analysis to investigate whether hours worked are better characterized as stationary or difference stationary. We conduct a battery of classical unit root and stationary tests, analyze the small-sample properties of some of the tests-statistics, explore encompassing tests and Bayesian odds ratios to ascertain if the more appropriate VAR model is the one in which hours per capita enter in levels or first-differences. The evidence gathered is in support of hours being stationary, which leads to the conclusion that per capita hours worked rise after a technology shock in the euro area. As for the responses of the remaining variables, our results are in line with the bulk of the literature.

CBmeter- a new medical device for early screening of metabolic diseases

Type 2 diabetes mellitus (T2DM) is a highly prevalent disease worldwide which is asymptomatic in about 44% of patients being critical to search for new ways of early diagnosis. Recent studies have demonstrated that the etiology of this disease may be associated with alterations in the function of the carotid body (CB), a chemosensor organ located within the bifurcation of the carotid artery. In animal models of metabolic syndrome it was observed that the CBs are overactivated, underlying diseases such as obesity, hypertension and T2DM. This discovery provided a new paradigm in the neuroendocrinology field, suggesting that diagnostic function of the CBs has predictive value for the development of metabolic diseases. Despite this fact, it is not common in clinical practice to look at the CBs as organs associated with endocrine dysfunction and we believe this is probably due to the nonexistence of a user-friendly, portable medical device that diagnosis the function of the CBs.info:eu-repo/semantics/publishedVersio

LisboaInterplay between DAF and viral proteins HA and NA modulates viral pathogenesis

"Host and viral factors contribute to define viral pathology. In this work, we explore the role of complement decay-accelerating factor (DAF) in activating complement and in modulating influenza A virus (IAV) infection via an interplay with the antigenic viral proteins hemagglutinin (HA) and neuraminidase (NA).(...)

As mãos, o coração, o mundo: O excesso e a intensidade na poesia de Carlos Drummond de Andrade

This article focuses in Carlos Drummond de Andrade’s poetry, specifically in the way how this poetic creates a net of connections between the hands, the hearth and the world. This study analyses the way how the concept of excess is manifested along the different stages of his poetic creation in relation with the self and the world. In the end of this article it is studied the idea of “Canto esponjoso” and the reflexivity about poetry and perception.Neste artigo é estudada a forma como, na poesia de Drummond, se tece uma rede em torno das mãos, do coração e do mundo. É feita uma análise sobre a forma como o conceito de excesso se manifesta na sua obra em relação com a figuração do eu e do mundo. No final deste artigo é estudada ainda a ideia de “canto esponjoso” e a reflexividade em torno da poesia e da perceção

Electric power generating bicycle

It is manifest the growing interest in both personal health and environmental issues. The device described on this paper contemplates both aspects: generating environment-friendly electric power while keeping fit. A car alternator excited through a 12V battery is coupled to a mountain bicycle, and this arrangement enables the lighting of six halogen lamps, if a cyclist pedals fast enough. Such a machine gives rise to the thought of a self-powered gymnasium. Considerable physical effort is required in order to make the lamps glow, which is pedagogical since it shows clearly that spending energy is much easier than generating it

Effects of Backpack Load and Trekking Poles on Energy Expenditure During Field Track Walking

This study evaluates the effects of the use of backpack load and trekking poles on feld track walking energy expenditure. Twenty male volunteer pole walkers (age: 22.70 ± 2.89 years; body mass: 77.90 ± 11.19 kg; height: 1.77 ± 0.06 m; percentage of body fat: 14.6 ± 6.0 %) walked at a self-selected pace on a pedestrian feld track over a period of more than six months. Each subject was examined at random based on four walking conditions: non-poles and non-load, with poles and non-load, nonpoles and with load, with poles and with load. Heart rate, oxygen uptake and energy expenditure were continuously recorded by a portable telemetric system. Non-load walking speed was lower during walking with poles when compared with no poles (p ≤ 0.05). Oxygen uptake, energy expenditure and heart rate varied signifcantly across different conditions. Our results suggest that the use of trekking poles does not influence energy expenditure when walking without an additional load, but it can have an effect during backpack load walking. Moreover, our results indicate that the use of trekking poles may not be helpful to lower the exertion perceived by the subjects when walking with an additional load.info:eu-repo/semantics/publishedVersio

Analysing the effects of different types of exercise on dyspnoea and fatigue in adults through COPD - systematic review and meta-analysis of randomised clinical trials

Background: Chronic obstructive pulmonary disease (COPD) is a heterogeneous lung condition, the main symptoms of which are dyspnoea and fatigue. Though exercise has been recommended for subjects with COPD, its benefits remain unclear. The aim of this study was to summarise, through a systematic review and meta-analysis, the available evidence on the effects of aerobic, resistance, stretching, and combined exercise on the main symptoms of COPD. Methods: Search was performed using the electronic databases PubMed and Web of Science. Randomised controlled trials (RCTs) with interventions based on aerobic, resistance and/or combined exercise published until July 2022 were identified. The effects were summarised based on standardised mean differences (95% confidence intervals) using random and fixed effect models. Results: Eight studies were selected, including a total of 375 subjects. The results obtained showed that resistance exercise, aerobic exercise and combined exercise seem to improve dyspnoea and fatigue symptoms in COPD subjects. Conclusions: In general, we can conclude that exercise-based interventions appear to improve the main COPD symptoms and may benefit quality of life in this population.info:eu-repo/semantics/publishedVersio